The invention relates to a multi-functional hand-tool, and more particularly, to a screwdriver for driving fasteners such as screws, bolts and the like. The screw-driver includes an offset shaft having at one end a means of engaging and retaining therein a bit and at an end opposite thereto a handle adapted to rotate relative to the shaft. A locking means pivotally attached to the handle is provided which is arranged to removably engage the shaft to prevent rotation of the handle.
When inserting or removing a fastener with a hand tool into or from a work surface, a workman""s efficiency is limited by the ability of the tool to translate mechanical force exerted by his hand to the fastener through rotary movement. For example, a tool such as a conventional screw-driver having a fixed handle mounted to a straight shaft imposes a physical limitation on the workman, allowing him to utilize only the torque which he can exert through his hand by the twisting of his wrist. Additionally, because the wrist cannot rotate completely about a circle, to complete a cycle of rotation with a conventional hand tool, the workman must periodically release his grip on the handle of the tool, rotate his hand back to a starting position and re-grip the tool handle to continue applying force.
Attempts have been made to provide rotary tools permitting better translation of the workman""s exertions. For example, U.S. Pat. No. 5,349,886 to Jin discloses a hand screwdriver including a freely rotatable handle and a bent shaft having an end recess which selectively bears against one of two conical protrusions within the handle. The conical protrusions provide a fixed position wherein the shaft is fixed to the handle and a rotatable position wherein the shaft is relatively rotated with respect to the handle. The screwdriver further includes a protective coating about the upper portion of the shaft adjacent to the handle for protecting a workman from electrical shock. A shortcoming of Jin is that no means is provided for preventing rotation of the handle relative to the shaft. As such, a workman cannot impart sufficient torque to a fastener when using the screwdriver of Jin to break the fastener loose from a work surface when tightly held therein. Likewise, a workman cannot provide sufficient torque to a fastener to tightly insert it into the work surface. A further shortcoming of Jin is that the protective coating about the shaft fails to envelop the entire shaft thereby needlessly exposing a workman to electrical shock from the unprotected portions of the shaft.
U.S. Pat. No. 1,642,569 to Winslow et al discloses a hand tool including a bent shaft having a handle rotatably attached to an end thereof. Contrary to Jin, a pressure plate is slidably mounted within the handle which slips through a slot therein and is bearable against the handle, selectively fixing the handle to the shaft. This way, a workman can impart increased torque to a fastener than if the handle and shaft were not fixable together. The screwdriver of Winslow et al however provides no suitable means of disengaging the pressure plate from the shaft. For example, a workman attempting to grip the pressure plate while wearing gloves to pull the plate out of the slot will have great difficulty doing so.
Therefore, despite the teachings of the prior art, a need still exists for a hand-powered tool which facilitates the translation of rotary motion from a workman""s hand to a fastener through a freely rotating angled shaft while providing practical means of preventing rotation of the shaft when needed. The present invention overcomes the shortcomings of the prior art and additionally provides a novel combination of hand-tool accessories with the multi-functional screwdriver of the present invention.
It is a primary object of the invention to provide a multi-functional screwdriver having an offset shaft rotatably connected to a handle wherein the shaft can be releaseably fixed to the handle to prevent rotation of the shaft relative to the handle.
It is a further primary object of the invention to provide a multi-functional screwdriver including an offset shaft rotatably mounted to a handle wherein the shaft can be releaseably fixed to the handle to prevent rotation of the. shaft relative to the handle and wherein the shaft is covered in its entirety with a non-conductive material.
It is a further primary object of the invention to provide a multi-functional screwdriver including an offset shaft rotatably mounted to a handle wherein the shaft can be releaseably fixed to the handle to prevent rotation of the shaft relative to the handle and wherein the shaft is magnetic.
It is a further primary object of the invention to provide a multi-functional screwdriver including an offset shaft rotatably mounted to a handle wherein the shaft can be releaseably fixed to the handle to prevent rotation of the shaft relative to the handle and wherein the handle includes a compartment for storing a plurality of bits.
It is a further primary object of the invention to provide a multi-functional screwdriver having an offset magnetic shaft covered in its entirety by a non-conductive sleeve, the shaft being rotatably mounted to a handle wherein a L-shaped locking member is pivotally attached to the handle which is releaseably engageable with the shaft to prevent rotation of the handle relative to the shaft and wherein the handle includes a compartment for storing a plurality of bits.
The screwdriver of the present invention comprises an offset shaft having two co-planer bends therein thus providing the shaft with a relaxed Z-shape; a handle having a resealable compartment for storing a plurality of bits, the handle being rotatably mounted to the shaft; a non-conductive sleeve circumposed about an entire length of the shaft; a magnetic bit driver connected at an end of the shaft opposite the handle; and a means of locking the shaft to the handle to prevent rotation of the handle relative to the shaft.
More particularly, the locking means of the invention includes a base fixed to the handle and a substantially L-shaped locking member connected to the base by a pin or hinge so that the locking member and base form a lever and fulcrum, respectively. An opening, hole or groove in the shaft which is adapted to receive an end of the locking member is provided which allows the workman to fix or unfix the shaft to the handle by pivoting the locking member either toward the shaft to prevent rotation of the handle relative to the shaft or toward the handle to prevent the rotation.
Preferably, the locking means includes the locking member as described above pivotable on a pin located within a depression within the handle. The depression conforms to the shape of the locking member and is long enough to accept the entire portion of the locking member that is adjacent to the handle when the locking member is pressed there against. The depression includes means of snapping or securing the locking member therein when the locking member is not engaged with the shaft. This way, the locking member, in part, can be securely held within the handle when the handle and shaft are in an unlocked position. Snapping means can include, for example, a ball and detent system or simply a portion of the depression having decreased width which allows the locking member to fit snugly therein.
Though it is preferred that the locking member comprise a substantially L-shape, it is anticipated that various modifications of the locking member can be made. For example, the locking member can include a rectangular member having rounded edges which conform the shape of the locking member to the handle and/or shaft to provide a more ergonomic design. The locking means therefore may be any fulcrum and lever system that allows the lever to engage the shaft, for example, at the opening or groove therein, thereby fixing the shaft to the handle.